/*
 * Designed and developed by 2023 skydoves (Jaewoong Eum)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.skydoves.orbital

import androidx.compose.animation.core.Animatable
import androidx.compose.animation.core.AnimationVector
import androidx.compose.animation.core.FiniteAnimationSpec
import androidx.compose.animation.core.TwoWayConverter
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.setValue
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.launch

internal class DeferredAnimation<T, V : AnimationVector>(
  private val coroutineScope: CoroutineScope,
  private val vectorConverter: TwoWayConverter<T, V>,
) {
  val value: T?
    get() = animatable?.value ?: target
  var target: T? by mutableStateOf(null)
    private set
  private var animatable: Animatable<T, V>? = null

  internal val isActive: Boolean
    get() = target != animatable?.targetValue || animatable?.isRunning == true

  fun updateTarget(
    targetValue: T,
    animationSpec: FiniteAnimationSpec<T>,
  ): T {
    target = targetValue
    if (target != null && target != animatable?.targetValue) {
      animatable?.run {
        coroutineScope.launch {
          animateTo(
            targetValue,
            animationSpec,
          )
        }
      } ?: Animatable(targetValue, vectorConverter).let {
        animatable = it
      }
    }
    return animatable?.value ?: targetValue
  }
}
